Section 30 in The Post Office Savings Certificates Rules, 1960
30. Conversion from one denomination to another.
(1)Certificates of lower denomination may be exchanged for a certificate or certificates of higher denomination of the same aggregate face value or a certificate of higher denomination may be exchanged for the certificates of lower denomination of the same value.(2)The date of the certificate or certificates issued in exchange shall be the same as that of the original certificate surrendered and not the date on which it is exchanged.
